Various kinds of SAFE AND ARM devices for various kinds of missiles and other weapons are well known. Some of these devices are concerned with detection of forces acting on the weapon to go to the ARMED state. Other devices involve the use of codes to prevent arming of a weapon unless a predetermined code has been satisfied. Coded SAFE and ARMING devices are particularly important for use with nuclear weapons, although their utility is by no means limited to such weapons. Coded SAFE and ARMING devices have, in recent years, tended to become extremely complicated and have relied heavily on electronics technology for coding. However, many of such systems are quite complex, are subject to failure, and can possibly be actuated inadvertently by stray electromagnetic signals or by deliberate unauthorized attempts to actuate the devices.
A well recognized need exists for a reliable electromechanical coded system which will permit a change from a SAFE state to an ARMED state in the event a predetermined code is received in appropriate sequence and will lock to DUD the unit in the event the code is not received in the proper sequence.